1. Field of the Invention
The present invention relates to a ceramic separation membrane structure in which a zeolite separation membrane formed on a ceramic porous body is repaired, and a repair method thereof.
2. Description of Related Art
In recent years, a filter made of ceramic material has been used to selectively recover only specific components from a multicomponent mixture (a mixed fluid). As compared with a filter made of organic polymer, the filter made of ceramic material is excellent in mechanical strength, durability, corrosion resistance and the like, and is therefore preferably applied to a water treatment or an exhaust gas treatment, or removal of suspended substances, bacteria, dust or the like in a liquid or a gas in a broad field such as a medical or food field.
As such filter, there is known a filter in which a zeolite membrane is formed on a ceramic porous body. When the zeolite membrane is formed on the ceramic porous body by hydrothermal synthesis, zeolite membranes can suitably be formed in most cells, however the presence of defects in some of the cells affected the quality as a product. When the hydrothermal synthesis is repeatedly performed to repair the defects, the membrane thickness of the portion other than the defects increases, and the permeation amount decreases.
In Patent Document 1, a method of repairing grain boundaries, cracks and pinholes of a zeolite membrane is disclosed. A coupling agent is brought into contact with one surface of the zeolite membrane and water is brought into contact with the other surface for the repair.
In Patent Document 2, a separation membrane disposed body is disclosed in which a sealing defect is less likely to be generated at a boundary portion between a separation membrane disposed on the surface of a porous substrate and a sealing portion. The boundary portion between the separation membrane and the sealing portion is provided with a coating zeolite.
In Patent Document 3, zeolite membranes are laminated to obtain a zeolite membrane having an excellent separation performance.